Lined tubing.



Patented Aug. 22; |899.

J. nowE.

UNED TUBING.

(Application filed Apr. 22, 1899.)

(N0 Model.)

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UNITED STATES PATENT EETCE.

JAMES ROVVE, OF CHICAGO, ILLINOIS.

LINED TUBING.

SPECIFICATION forming part of Letters Patent No. 631,328, dated August 22, 1899.

Application tiled April 22, 1899. Serial No. 714,123. (No model.)

To a/ZZ whom Lt may concern:

Be it known that I, JAMES ROWE, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Lined Tubing; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a novel construction in lined tubing adapted for use in molds for casting printers rollers and other purposes, the object being to provide a device of this character which is protected against denting, bending, and becoming otherwise untrue and which can be interiorly finished without danger of being affected in the manner above described; and it consists in the features of construction hereinafter fully described and claimed.

The accompanying drawing, illustrating my invention, represents a transverse sectional view of a tube constructed in accordance with my invention.

In the manufacture of molds for casting printers rollers a great difcu-lty has always been experienced in producing a true cylinder and one having sufficient strength to remain true. These molds are generally made of brass tubing, and to obtain the requisite strength heavy tubing has been employed. This is very expensive and besides fails to entirely overcome the objections noted. Various devices have been tried, such as inclosing brass tubing in a steel tube, and I have made experiments in this direction also, but without attaining the desired results. After many experiments I have finally succeeded in producing the device shown in the accompanying drawing, which has proved entirely satisfactory.

My present invention consists in providing two concentric tubes A and B of the same or different materials and of sufficiently different diameters to leave an annular space between them which is filled with compressed cement or other suitable' material introduced in a plastic condition. The inner tube B is preferably a light brass tube, while the tube A may be ordinary gas-pipe. The cement is preferably a mixture of litharge and glycerin in the proportion by weight of approximately three parts litharge to one part glycerin, which sets quickly and is not affected by temperature, besides being able to withstand high pressures. The cement mixture is introduced between said tubes under very high pressure by means of suitable apparatus and is held under such pressure until it is set. In order to produce a true inner tube, the latter is rst placed over a mandrel of corresponding diameter and the degree of pressure brought to bear upon the cement filling is sufficient to force the inner tube so closely upon the mandrel as to press out any irregularities in the inner tube.

The advantages of this construction are many. In the first place I am enabled to cmploy an outer casing of unnished pipe, which could not be employed were the inner tube to be forced into and t snugly within the outer tube. Thus I avoid the expense of finishing the outer tube interiorl y. In the second place I am enabled to employ a very light inner tube, since the latter is not subjected to any strain, as Would be the case were it to be forced into the outer tube, thus enabling me to employ a lighter tube than would be possible where the two tubes are fitted to each other. Third, the increased thickness of the wall of the complete tube due to the layer of cement so stiffens and reinforces the two tubes as to enable them to bear far greater strain without bending or affecting them in any way as to enable me to employ a much thinner and lighter outer tube than would otherwise be possible. Fourth, by the use of thin tubes I greatly decrease the weight of the finished tube, while at the same time I increase its strength to a far greater degree than would be possible without the compressed filling. Fifth, by the use of light tubing I save a great deal of expense in material, and, sixth, the ease of manufacturing the tube makes it far less expensive than any other form of lined tubing. Y

Molds for printers .rollers are frequently eight and ten feet in length, so that it will readily be seen that it is a difficult matter to produce a tube which will remain absolutely true Without greatly increasing the cost and weight of the mold.

My device can obviously also be used for introduced and allowed to harden under a pressure sufficient to contract said inner tube upon a mandrel inserted therein.

l. As a new article of manufacture, a tube comprising two concentric tubes and an interposed layer of compressed filling, said tube having the characteristics hcreinbefore set forth.

5. As a new article of manufacture, a tube comprising two concentric tubes and an interposed layer of compressed cement, said tube having the characteristics hereinbefore set forth, obtained by introducing said filling i in plastic condition under pressure and alj lowing it to set while under such pressure.

pressure and allowed to harden in the presence of such pressure.

3. A tube comprising` an outerheavy tube, and a light concentric inner tube, an annular space between said tubes, and a compressed fillingin said annular space, said filling being In testimony whereof I ai'ix my signature in presence of two witnesses.

JAMES ROVVE. Witnesses RUDOLPH WM. Lorz, WM. B. SNoWHooK. 

